Reduce work of calculating outbound device pokes #1318

Job	Run time
lint-crlf	6s
changes	2s
check-lockfile	4s
lint-newsfile	31s
lint	50s
Typechecking	1m 22s
check-schema-delta	36s
check-sampleconfig	36s
lint-pydantic	48s
lint-clippy	0s
lint-clippy-nightly	0s
lint-rustfmt	0s
linting-done	2s
calculate-test-jobs	6s
trial-olddeps	6m 53s
complement (monolith, SQLite)	12m 26s
portdb (3.8, 11)	2m 44s
trial-pypy	0s
complement (monolith, Postgres)	12m 58s
portdb (3.11, 15)	2m 58s
complement (workers, Postgres)	20m 59s
cargo-bench	0s
cargo-test	0s
trial (3.8, sqlite, all)	4m 9s
sytest (focal)	8m 2s
trial (3.8, postgres, 11, all)	10m 11s
sytest (focal, postgres)	9m 49s
trial (3.8, sqlite)	4m 17s
sytest (focal, multi-postgres, workers)	13m 19s
sytest (focal, multi-postgres, workers, asyncio)	19m 31s
export-data	2m 8s
tests-done	4s
	2h 15m 31s

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